Carbazole-alkyl ketones



Patented Dec. 7, 1937 UNlTE D STATES P'ATENTKOFFI'CE ,CARBAZOLE-ALKYL KETONES Anderson W. Ralston and Carl W. Christensen, Chicago, Ill., assignors to Armour and Company, Chicago, 111., a corporation of Illinois No Drawing. Application September 119, 1936,

Serial No. 101,675

5 Claims. (on. zen-.46)

This invention relates to aralkyl ketones and it comprises, as new compounds, ketones having the generic structure wherein R is a carbozole radical and R is an alkyl radical having eleven, thirteen, fifteen, or seventeen carbon atoms; and it further comprises diketones having the structural formula RCRGR H l 0 wherein R is a carbazole radical and R is an alkyl radical having eleven, thirteen, fifteen, or

I making candles, etc., and in but relatively few instances have they been used as raw materials in what might be termed as the fine organic chemical field.

We have now discovered anew class of com pounds which can be made from .thehigher fatty acids and which have chemical and physical properties of marked technical and commercial interest. We have discovered that the higher fatty acid chlorides, such as stearyl chloride, myristyl chloride, lauryl chloride, caproyl chloride, and other acid chlorides derived from, and. corresponding to the higher fatty acids, can be made to react with carbazole, .or substituted carbazoles, to give aralkyl ketones having valuable properties which suit them for use in many technical applications. These aralkyl ketones are waxy solids, and can be crystallized from organic solvents such as benzene, alcohol and others to give pure ketones'. The crystalline products, when melted and allowed to cool, yield substances of clearly defined Waxy character, ap-

pearance and feel. We have discovered that they are excellent dielectrics and can'be used in electrical insulation. We have also discovered that these new substances are desirable constituents in waxing and polishing compounds. When added to lubricating oils, the ketones of the present invention confer beneficial properties on the oil. The ketones of our invention have pronounced antifoaming properties and can thus be added to aqueous liquids such as boiler water to prevent foaming therein.

In its broad aspects, our invention comprises new products having the generic formula R-CR' wherein R is a carbazole radical which may be 7 substituted or not, and R. is an alkyl radical corresponding to the alkyl radical of a higher fatty acid. Byhigher fatty acid we mean those fatty acids having twelve or more carbon atoms. We have also discoveredthat diketones containing two alkyl radicals attached to a carbazole nucleus can be prepared. Thus, a s an example, one 1' of the new products fallingwithin the scope of our invention is 2-.stearylcarbazole:

V l Inthis case, the 0171 135, 01' heptadecyl radical,

is the alkyl radical or stearic acid, C17H35COOH. Thisparticular ketone has a melting point of Another typical ketone falling within the generic scope of our invention is 2-lau'rylcarbazolez 2,8-distearylcarbazole (melting point 161462"- C.)

2,8-dipalmitylcarbazole (melting point 162 C.)

CHEM-4]?- O iii) 2,8-dimyristylcarbazole (melting point 169 C.)

2,8-dilaurylcarbazole (melting point 176 C.)

All of the ketones of our invention can be made by Friedel-Crafts reaction.

Thus, for example, when we wish to make 2-stearylcarbazole we start with carbazole and stearyl chloride. The stearyl chloride can be made in any of the known ways from stearic acid. Generally the stearic acid is treated with phosphorus pentachloride or other chlorinating reagent commonly used for converting aliphatic carboxylic acids to their corresponding acid chloride. Thirty-five parts by weight of carbazole are reacted with 50 parts of stearyl chloride, using approximately parts by weight of carbon disulfide as a solvent. Hydrogen chloride is evolved and the stearyl radical thereby attached to the nitrogen, giving N-stearylcarbazole. The mixture is then cooled in an ice bath and about 50 parts by weight of aluminum chloride are added with constant stirring. This rearranges the N-stearylcarbazole to give Z-stearylcarbazole. The reaction mixture is then poured onto a mixture of ice-dilute hydrochloric acid to hydrolyze any complex aluminum chloride compound formed in the reaction. Finally the resulting mixture is placed in a flask and subjected to steam distillation. This removes the carbon disulfide used as a solvent and also any excess carbazole. The ketone does not distill over with the carbon disulfide and can be separated from the aqueous solution of aluminum chloride in the distillation flask by simple decantation. It is then taken up in carbon tetrachloride, benzene, or other organic solvent and crystallized therefrom. In the preparation of the disubstituted carbazoles, such as 2,8-distearylcarbazole, the same procedure is followed with the exception that 2 mols of stearyl chloride are used instead of 1.

We can start with any acid chloride of the higher fatty acids. Generally we start with the acid chlorides of fatty acids of twelve or more carbon atoms since these fatty acids are readily available and cheap. Our invention is, therefore, not limited to the specific compounds described above, since we are the first to describe aralkyl ketones, or mixed ketones, in which the aryl group is a carbazole radical and the alkyl group, or groups, is the alkyl radical of a higher fatty acid.

We believe that the course of the reaction for the formation of the ketones is that given above but we do not wish to be bound thereby. Likewise under some conditions it is possible that the substituent COR' group may take some other position than that stated. In other words isomeric compounds may form and indeed mixtures of various isomers may be prepared. Consequently we define our invention broadly in the appended claims and do not wish to be limited to specific ketones except as indicated in the claims.

All of the ketones can be prepared as described .for 3-stearylcarbazole and consequently we limit the description of our procedural steps to this substance. Generally the quantities of reacting substances used are those required by stoichiometric calculation.

In the interest of uniformity in nomenclature we are defining our compounds in the foregoing by means of the International nomenclature. In this method of identifying the position of substituent groups the carbon atoms are numbered beginning with the right-hand top carbon of the carbazole radical and going clockwise. Thus in the International nomenclature the stearylcarbazole is identified as Z-stearylcarbazole. In the chemical abstracts nomenclature the compound would be known as 3-stearylcarbazole. And in the appended claims we refer to the alkyl group in the ketone as undecyl, tridecyl, pentadecyl or heptadecyl as the case may be, since such definition is more appropriate when identifying the substituent alkyl groups in the ketones. Thus, for example, that ketone wherein R is heptadecyl is identical with 2-stearylcarbazole, that compound where R is undecyl is identical with 2-laurylcarbazole, etc.

Having thus described our invention, what we claim is:

1. An aralkyl ketone having the structure:

wherein R is an alkyl radical chosen from the group consisting of undecyl, tridecyl, pentadecyl and heptadecyl.

2. An aralkyl ketone having the structure:

wherein R is an alkyl radical chosen from the as in claim 1 wherein R is as in claim 1 wherein R is as in claim 2 wherein R is ANDERSON W. RALSTON. CARL W. CHRISTENSEN. 

